LSM330D Datasheet, PDF (23/66 Pages) STMicroelectronics – Low power mode

LSM330D
Functionality
4.2
Gyroscope digital main blocks
Figure 5. Gyroscope block diagram
Out_Sel
00
01 _DataReg
0
FIFO
LPF2
10
32x16x3
11
ADC LPF1
HPF
1
I²C
SPI
HPen
INT_Sel
10
11
Interrupt
01
generator
00
SCR REG
CONF REG
INT1
AM07230v1
4.3
4.3.1
FIFO
The LSM330D embeds 32 slots of 16-bit data FIFO for each of the three output channels:
yaw, pitch and roll. This allows consistent power saving for the system, since the host
processor does not need to continuously poll data from the sensor, but can wake up only
when needed and burst the significant data out from the FIFO. This buffer can work
accordingly in five different modes: Bypass mode, FIFO mode, Stream mode, Bypass-to-
Stream mode and Stream-to-FIFO mode. Each mode is selected by the FIFO_MODE bits in
the FIFO_CTRL_REG_G register. Programmable watermark level, FIFO_empty or
FIFO_Full events can be enabled to generate dedicated interrupts on the DRDY_G/INT2_G
pin (configured through the CTRL_REG3_G register) and event detection information is
available in the FIFO_SRC_REG_G register. Watermark level can be configured to WTM4:0
in the FIFO_CTRL_REG_G register.
Bypass mode
In Bypass mode, the FIFO is not operational and for this reason it remains empty. As
described in Figure 6 below, for each channel only the first address is used. The remaining
FIFO slots are empty. When new data is available the old data is overwritten.
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